The long-term objectives of the research are to develop an optimal tracking technology for use with MRI scanners. The specific aims are to complete the development of the tracking system; to test its use with image-guided, minimally-invasive diagnostic and therapeutic clinical applications for neurosurgery, breast biopsy, and prostate brachytherapy; and to complete all tasks necessary to obtain regulatory clearance for marketing. Current tracking technologies for MRI have many limitations and improved technology can expand the use of MRI-guided interventions to many clinical fields, reduce healthcare costs, and improve the outcome of patients. During the Phase II project we plan to complete the prototype of the commercial tracking system, to develop a new type of low-cost, disposable sensors, to install this prototype in a leading clinical center for MRI-guided interventions, to test its accuracy and reliability, and to use it with three clinical applications - neurosurgery, breast-biopsy, and prostate brachytherapy. The completion of the technical development and the demonstration of clinical applications will enable the filing of premarket notification to the FDA and initial marketing of the tracking system. Using advanced microelectronic fabrication methods to develop the tracking sensors has the potential to provide innovative micro-sensors for new intrabody tracking applications. PROPOSED COMMERCIAL APPLICATION: 1. Tracking systems for MRI scanners (initial installation of hardware and software, service, upgrades). 2. Disposable tracking sensors: small adhesive pads to track head position and motion for diagnostic and interventional brain MRI scanning; disposable sensors attached to or integrated into single-use-devices-biopsy and aspiration needles, catheters; sensors integrated into multiple-use devices - minimal invasive surgery tools, endoscopes.